Contact spring set



Dec. 20, 1960 H. v. ALEXANDERSSON 2,965,739

CONTACT SPRING SET Filed April 23, 1957 firroRA/Frs United States PatentCONTACT SPRING SET Harald Valdeniar Alexandersson, Lidingo, Sweden,assignor to Telefonaktiebolaget L M Ericsson, Stockholm, Sweden, acorporation of Sweden Filed Apr. 23, 1957, Ser. No. 654,514

Claims priority, application Sweden May 5, 1956 9 Claims. (Cl. 200-166)The invention relates to sets of contact springs for electromagneticrelays and other electromagnetic switching devices.

Contact spring sets for electromagnetic relays are usually provided withcontact springs of the Hat type. Spring sets have also been made withwires as contact springs. By bending the wires differently it isachieved that the dilferent contact springs may press against each otherwith suitable contact pressures. However, in manufacture it istroublesome to obtain the right contact pressures and for a few types ofcontact springs it is also difficult to obtain a great variation ofcontact combinations. A simple and cheap manner of obtaining a contactspring set, which requires a small adjustment and which provides a verygreat diversity of contact combinations with only one design of thecontact spring, is the object of the invention described below.

The contact spring set is built up by suitably elastic, straight wires,which at their movable ends are forming contact with a rigid contactdevice, which preferably has no outer fixed connections. The contactpressures between the wires and the rigid contact device is obtained insuch a way that the contact wires at the mounting are brought out oftheir non-tensioned condition to a position either above or below therigid contact device, so much that, when resting against the device,they give a suitable contact pressure. Desired contact combinations areobtained in such a way that the rigid contact device, which for eachtype of relay may be of a standardized design, during the mounting ofthe spring set, by punching out of holes or recesses, is given thecontact combination which is desired for said relay. The rigid contactdevice consists suitably of a bar of insulating material, to which ametal strip has been fixed, which is so shaped that by means of recessesthrough the metal strip it obtains the desired contact combination. Thecontact spring set is furthermore provided with a lifting bar ofinsulating material with two rows of holes or grooves, the upper row ofwhich is intended for contact springs, which produce breaks and thelower row for contact springs, which produce makes. By making thegrooves in the lifting bar sufliciently great it is possible to achievethat a contact spring either is not at all operated or that it isoperated later than the other contact springs during the movement of therelay.

The contact spring set may either be made with the contact springslocated in one plane and the free ends of the wires may thereby bearbitrarily placed above or below the rigid contact device, or with thecontact wires located in two parallel planes, the free ends of the upperwires thereby being all located above the rigid contact device and thefree ends of the lower ends all located below the rigid contact device.

The invention will now be described more in detail with reference to theannexed drawing. Fig. 1 shows a side view of a relay with a contactspring set, Fig. 2 the same relay seen from in front, Fig. 3 is anenlarged view 2,965,739 Patented Dec. 20, 1960 of the contacts and Fig.4 is an enlarged illustration of an altered design of the rigid contactdevice.

On a normal knife-edge relay with a relay angle bar 1, an armature 2, arelay core and a winding 3 there is located a contact spring set. Thislatter consists in the shown example of seven contact springs 4 fixed inone end to a plinth 5 of insulating material, a plate 6 supported by theplinth, a rigid contact device 7 and a lifting bar 8, which uponmovement of the armature operates the springs 4. The rigid contactdevice consists of a bar of insulating material 9 mounting a metal strip10. The metal strip is cemented at the bar and is at its edge providedwith wedge-shaped contact points 11, at which the contact springs aremaking contact. The contact springs, which suitably consist of elastic,in nontensioned condition straight wires, are at their movable ends inthe contact point provided with tubes of contact material 12, a twincontact effect thus being obtained when the contact tubes rest in thewedge-shaped contact points 11. When the fixed, elastic contact wires atthe mounting are brought to a position either above or below the rigidcontact device 7, they must be bent so much from their straight,non-tensioned condition, that they obtain a suitable contact pressurewhen resting against a contact point 11. The rigid contact device isheld in its position by being stretched between two arms 13, whichextend from the plate '6. The lifting bar '8 is fixed between twosprings 14, 15, which also extend from the plate 6. The lifting bar isprovided with two rows of holes or grooves 16, 17, through which thecontact wires 4 protrude. The spring 14 is given so strong a pressuredownwards that it can overcome the up-pressure from all contact wiresbrought through the lower row of grooves 17. Normally all wires orsprings 4 in the upper row will in non-operated condition rest againstthe rigid contact device and all springs 4 in the lower row will be keptby the lifting bar 8 at a certain distance from the rigid contactdevice. Upon operation of the relay the armature operates the liftingbar, which is moved upwards. Then the springs 4 in the upper row aredeflected out of engagement and the springs 4 in the lower row followthe movement upwards until they stop, pressed against the rigid contactdevice by their own spring tension. If certain of the grooves 16, 17 inthe lifting bar are made a little larger it will be possible to achievethat the corresponding springs 4 either will be not at all operated bythe lifting bar or later than the other springs. Not operated springs 4are used as fixed connections to the contact device and springs 4, whichare operated late, may be used to produce delayed contact functions.

The metal strip 10 on the bar 9 is slotted between each two adjacentnotches 11. The slots 18 extend from opposite longitudinal edges of thestrip so as to form narrow bridges 10' between each adjacent pair ofnotches 11. By severing selected ones of these bridges by means of holes19, several effective preselected contact combinations may be obtainedwhen bar 8 is actuated. This affords the advantage that the manufactureof the contact device may be standardized and the device adjusted for adesired contact combination after manufacture. In the example accordingto Fig. 2, holes 19 are cut, counting from the left of the figure,between the third and fourth contact notches and between the fifth andsixth. The effective contact combination can be further varied byvarying the depths of grooves 16. In the example, the grooves 16 for thefirst and fifth springs are so deep that the first and fifth springscannot be operated by the lifting bar 8 and will thus remain in thenotches 11. The groove 17 for the sixth spring is also so deep that thisspring will remain in its notch 11. With such adjustment, upon upwardmovement of the bar 8, there will be effected at the second and thirdnotches, counting from the left, a switching, at the fourth notch amake, and at the seventh notch a break. Hence, the circuit between thefirst and the second spring is broken and switched to a circuit betweenthe first and the third spring, a circuit between the fourth and fifthsprings is made, and a circuit between the sixth and seventh springs isbroken.

In the embodiments described, all the contact wires 4 are secured to theplinth 5 in one plane. As stated before, all the wires are initiallystraight, and each individual wire, during assembly, may be placed asdesired into either its respective upper notch 11 and groove 16 or lowernotch 11 and groove 17. The contact combinations thus obtainable, can befreely selected as required. It is to be noted that only one type ofcontact wire is required. The total number of contact points is, ofcourse, limited by the practical width of the relay.

While in the embodiment heretofore described, the contact Wires are allmounted in one plane, the contact wires may also be mounted in twoplanes so that each pair of opposite notches 11 has assigned thereto arespective wire. As shown at the left in Fig. 4, the upper row of wirespasses through the upper row of grooves 16, Fig. 3, in the lifting barand the lower row is placed in the lower row of grooves 17. Thepossibility of varying selectively the possible contact combinations isthen somewhat limited, but still considerably greater than by means ofthe known constructions. When each notch has a respective wire 4, themetal strip for the fixed device 7 can be formed as shown in Fig. 4. Insuch arrangements the contact wires can be disposed to effect manycombinations, the only limitation being that it is not possible to usethe wires in the upper row as make contacts and the wires in the lowerrow as break contacts. The contact combinations in this case areobtained by severing bridges such as 41, 42 in the metal between thecontact points. Thus, if the narrow bridges at 41 and 42 are cut, thetwo wires located farthest to the left in the upper row may, togetherwith the wire located farthest to the left in the lower row, be used fora switching similar to that described in connection with Fig. 2. Thesecond wire in the lower row is connected with the other contact pointsto the right by way of the bridge 43 and may therefore be included inother combinations.

The invention is of course not limited to the construction describedhere. It may advantageously be used in the majority of known relayconstructions and also for switches or the like. The used contactsprings are shaped as round wires. Of course these may be designed indifferent ways without departing from the principle of the invention.The round wires have proved to be very suitable, but other springs,particularly such that take up small room laterally, may be used, ifduring the mounting they give a suitable contact pressure when restingagainst the rigid contact device.

I claim:

1. A set of contact springs for an electromagnetic switching device,said set comprising several flexible springy wires, a mounting meansfixedly mounting said wires at one end in coplanar relationship, astationary contact device including an elongated conductive memberextending transversely of the plane of said wires and having contactpoints at opposite longitudinal sides, one for each contact wire, saidwires being flexed out of said plane and overlying contact points onopposite sides of said device to bias the overlying wire portions towardthe respective contact points with pressure contact for connecting thewires through said member, and a lifting member displaced transverselyof said wire plane, said member being engaged with the flexed wires fortransverse movement of the latter in unison with the lifting memberwhereby a transverse displacement of the member varies the operationalpositions of said overlying wire portions relative to the respectivestationary contact points correspondingly. 7

2. A set of contact springs according to claim 1 wherein said contactpoints on the stationary conductive member are of substantially V-shapedcross section and face in opposite directions.

3. A set of contact springs according to claim 1 wherein said stationaryconductive -member includes recesses between the contact points whichrecesses underlie the positions occupied by the Wires in relation to thestationary contact points in response to a displacement of said liftingmember.

4. A set of contact springs according to claim 1- wherein saidstationary contact device comprises an insulation-backed metal stripmounting at each end said contact points, said strip being divided inselected electrically separated portions conected to contact points, theselection of the division of said metal strip controlling the contactconnections effected by displacement of said lifting member.

5. A set of contact springs according to claim 1 wherein said liftingmember comprises an axially dis placeable insulation bar having twolongitudinally spaced rows of grooves, one for each wire, the grooves ofsaid rows holding in one displaced position of the bar selected wires inpressure contact with contact points at one end of the contact device toform break contacts and other selected wires in disengagement from thecontact points at the other end of the contact device to form makecontacts and in another displaced holding break contacts in thedisengaged position and make contacts in the engaged position.

6. A set of contact springs according to claim 5 wherein selected onesof the grooves associated with break contact wires have a longitudinallength such that the respective wires remain in the contact engagingposition upon displacement of the lifting member whereby said breakcontacts constitute operationally permanent contact connections.

7. A set of contact springs according to claim 5 wherein selected onesof said grooves have a longitudinal length different from that of otherselected grooves whereby displacement of the wires in relation to thesaid contact points is staggered upon displacement of said liftingmember.

8. A set of contact springs according to claim 5 wherein said mountingmeans support said contact wires in two superimposed but spaced apartparallel planes, the wires in one plane engaging the grooves in one rowand the wires in the other plane engaging the grooves in the second row,all the wires in one plane forming break contacts and all the wires inthe other plane forming make contacts.

9. A set of spring contacts according to claim 8 wherein said stationarycontact device comprises a metal strip mounting said contact pointsalong its two longitudinal edges, said strip having slots extendingtransversely from both longitudinal edges between each two contactpoints and each terminating short of a slot extending from therespective opposite longitudinal edge and said strips further includingapertures between each two contact points situated between therespective inner slot ends, the strip material between the slots and theapertures constituting readily severable bridges, severance of selecedones of said bridges controlling the combination of contact connectionseffected by displacement of said lifting member.

References Cited in the file of this patent UNITED STATES PATENTS1,133,786 Babcock Mar. 30, 1915 2,488,669 Knos Nov. 22, 1949 2,671,840Sway Mar. 9, 1954 2,683,192. Vincent July 6, 1954 2,686,850 Early Aug.17, 1954

